Cold flow resistant compositions containing rubber and a block copolymer

ABSTRACT

Disclosed are cold flow resistant and dimensionally stable compositions containing a diene rubber and a conjugated diene monovinylarene block copolymer, and generally, these compositions have solutions viscosities and cold flows that are less than that of the diene rubber. Methods for reducing cold flow and for storage-stabilizing bales of diene rubbers also are disclosed.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of co-pending U.S. patentapplication Ser. No. 13/789,786, filed on Mar. 8, 2013, now U.S. Pat.No. 8,933,171, which claims the benefit of U.S. Provisional ApplicationSer. No. 61/644,016, filed on May 8, 2012, the disclosures of which areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Many commercial grades of rubber are shipped and stored in the form of asolid slab, often referred to as a bale. However, over time andparticularly at elevated temperatures, the bale of rubber can exhibitcold flow, manifesting in dimensional changes of the bale. It would bebeneficial to have a rubber composition that has greater resistance tocold flow during shipping and/or long-term storage, and moreover, whenconditions of higher temperature may be encountered. Accordingly, it isto these ends that the present invention is directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

Cold flow resistant and dimensionally stable compositions are disclosedand described herein, and such compositions can comprise (a) a dienerubber, and (b) a conjugated diene monovinylarene block copolymer. Thesecompositions can be characterized as having a solution viscosity that isless than the solution viscosity of the diene rubber, as well as a coldflow that is less than the cold flow of the diene rubber.

Another embodiment of this invention is directed to a method forconcurrently reducing the cold flow and the solution viscosity of adiene rubber, and in this embodiment, the method can comprise combiningthe diene rubber with a conjugated diene monovinylarene block copolymerto form a cold flow resistant composition. The solution viscosity of thecomposition can be less than the solution viscosity of the diene rubber,and the cold flow of the composition can be less than the cold flow ofthe diene rubber.

Embodiments of the invention also are directed to methods forstorage-stabilizing a bale of diene rubber. One such method can compriseadding a conjugated diene monovinylarene block copolymer to the dienerubber to form a cold flow resistant composition. The resultant coldflow composition can have both a solution viscosity and a cold flow thatis less than the respective solution viscosity and cold flow of thediene rubber.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain embodiments maybe directed to various feature combinations and sub-combinationsdescribed in the detailed description.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Regarding claim transitional terms or phrases, the transitional term“comprising,” which is synonymous with “including,” “containing,”“having,” or “characterized by,” is inclusive or open-ended and does notexclude additional, unrecited elements or method steps. The transitionalphrase “consisting of” excludes any element, step, or ingredient notspecified in the claim. The transitional phrase “consisting essentiallyof” limits the scope of a claim to the specified materials or steps andthose that do not materially affect the basic and novelcharacteristic(s) of the claimed invention. A “consisting essentiallyof” claim occupies a middle ground between closed claims that arewritten in a “consisting of” format and fully open claims that aredrafted in a “comprising” format. Absent an indication to the contrary,describing a compound or composition as “consisting essentially of” isnot to be construed as “comprising,” but is intended to describe therecited component that includes materials which do not significantlyalter the composition or method to which the term is applied. Forexample, a composition consisting essentially of a material includesimpurities and additives typically present in a commercially produced orcommercially available sample of the recited material. When a claimincludes different features and/or feature classes (for example, amethod step, composition features, and/or property features, among otherpossibilities), the transitional terms comprising, consistingessentially of, and consisting of, apply only to the feature class towhich it is utilized, and it is possible to have different transitionalterms or phrases utilized with different features within a claim. Forexample, a method can comprise several recited steps (and othernon-recited steps), but utilize a composition consisting of a specificmaterial and other components; alternatively, consisting essentially ofa specific material and other components; or alternatively, comprising aspecific material and other components and other non-recited components.

Therefore, while compositions and methods are described in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a cold flow resistantcomposition provided in an embodiment of the invention can comprise, oralternatively, consist essentially of, or alternatively, consist of, adiene rubber and a conjugated diene monovinylarene block copolymer.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “aconjugated diene monovinylarene block copolymer,” “a diene rubber,”etc., is meant to encompass one, or mixtures or combinations of morethan one conjugated diene monovinylarene block copolymer, diene rubber,etc., unless otherwise specified.

The term “polymer” is used herein generically to include homopolymers,copolymers, terpolymers, and so forth, while a “copolymer” is usedgenerically to include copolymers, terpolymers, and so forth. Thus,“polymer” and “copolymer” encompass polymeric materials derived from anymonomer and comonomer (one or more than one) disclosed herein.

As used herein, a “conjugated diene” refers to an organic compoundcontaining conjugated carbon-carbon double bonds and often a total of 4to 12 carbon atoms, such as 4 to 8 carbon atoms. Exemplary conjugateddienes can include, but are not limited to, 1,3-butadiene,2-methyl-1,3-butadiene, 2-ethyl-1,3-butadiene,2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-butyl-1,3-octadiene, andthe like, as well as mixtures thereof. For example, in some embodimentsdisclosed herein, the conjugated diene can be 1,3-butadiene. A unit of apolymer, wherein the unit is derived from polymerization of a conjugatediene monomer, is referred to as a “conjugated diene unit.”

As used herein, “monovinylarene” refers to an organic compoundcontaining a single carbon-carbon double bond, at least one aromaticmoiety, and often a total of 8 to 18 carbon atoms, such as 8 to 12carbon atoms. Exemplary monovinylarenes can include, but are not limitedto, styrene, alpha-methylstyrene, 2-methylstyrene, 3-methylstyrene,4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene,4-n-propylstyrene, 4-t-butylstyrene, 2,4-dimethylstyrene,4-cyclohexylstyrene, 4-decylstyrene, 2-ethyl-4-benzylstyrene,4-(4-phenyl-n-butyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, andthe like, as well as mixtures thereof. For example, in some embodimentsdisclosed herein, the monovinylarene can be styrene. A unit of apolymer, wherein the unit is derived from polymerization of amonovinylarene monomer, is referred to as a “monovinylarene unit.”

A “conjugated diene monovinylarene block copolymer” is a polymercomprising monovinylarene units and conjugated diene units. The polymercomprises one or more blocks, wherein each block comprisesmonovinylarene units and/or conjugated diene units. Any particular blockcan comprise either or both monovinylarene units or conjugated dieneunits. If it comprises only one type of unit, it can be termed a“monoblock.” If it comprises both, it can be termed a mixed block.Exemplary mixed blocks can include, but are not limited to, randomblocks, tapered blocks, stepwise blocks, or any other type of mixedblock.

A mixed block is “tapered” when both (a) the mole fraction of conjugateddiene units in a first section of the block is higher than the molefraction of conjugated diene units in a second section of the block,wherein the second section of the block is closer to a given end of theblock, and (b) condition (a) is true for substantially all sections ofthe block. Depending on the size of the sections being considered,condition (a) may not be true for all sections, but if so, will be nottrue at no more than about the level expected by chance.

A mixed block is “random” when the mole fractions of conjugated dieneunits and monovinylarene units in a section of the block aresubstantially the same as the mole fractions of conjugated diene unitsand monovinylarene units in the entire block. This does not preclude thepossibility of sections of the block having regularity (i.e., appearingnon-random), but such regular sections will typically be present at nomore than about the level expected by chance.

Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of theinvention, the typical methods and materials are herein described.

All publications and patents mentioned herein are incorporated herein,in their entirety, by reference for the purpose of describing anddisclosing, for example, the constructs and methodologies that aredescribed in the publications, which might be used in connection withthe presently described invention. The publications discussed throughoutthe text are provided solely for their disclosure prior to the filingdate of the present application. Nothing herein is to be construed as anadmission that the inventors are not entitled to antedate suchdisclosure by virtue of prior invention.

Applicants disclose several types of ranges in the present invention.When Applicants disclose or claim a range of any type, Applicants'intent is to disclose or claim individually each possible number thatsuch a range could reasonably encompass, including end points of therange as well as any sub-ranges and combinations of sub-rangesencompassed therein. A representative example follows for the wt. % ofthe conjugated diene monovinylarene block copolymer in a cold flowresistant composition in an embodiment of this invention. For example,by a disclosure that the composition comprises from about 15 to about 30wt. % of the conjugated diene monovinylarene block copolymer (based onthe total weight of the composition), Applicants intend to recite thatthe weight percentage can be equal to about 15, about 16, about 17,about 18, about 19, about 20, about 21, about 22, about 23, about 24,about 25, about 26, about 27, about 28, about 29, or about 30 wt. %.Additionally, the weight percentage can be within any range from about15 to about 30 wt. % (for example, the weight percentage can be in arange from about 15 to about 25 wt. %), and this also includes anycombination of ranges between about 15 and about 30 wt. %. Likewise, allother ranges disclosed herein should be interpreted in a manner similarto this representative example.

Applicants reserve the right to proviso out or exclude any individualmembers of any such group, including any sub-ranges or combinations ofsub-ranges within the group, that can be claimed according to a range orin any similar manner, if for any reason Applicants choose to claim lessthan the full measure of the disclosure, for example, to account for areference that Applicants may be unaware of at the time of the filing ofthe application. Further, Applicants reserve the right to proviso out orexclude any individual substituents, analogs, compounds, ligands,structures, or groups thereof, or any members of a claimed group, if forany reason Applicants choose to claim less than the full measure of thedisclosure, for example, to account for a reference that Applicants maybe unaware of at the time of the filing of the application.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure provides cold flow resistant compositionscontaining a diene rubber, methods for concurrently reducing both thecold flow and the solution viscosity of a diene rubber, and methods forstorage-stabilizing a bale of a diene rubber.

Cold Flow Resistant Compositions

Some embodiments of this invention are directed to cold flow resistantcompositions which can comprise (a) a diene rubber, and (b) a conjugateddiene monovinylarene block copolymer, while other embodiments aredirected to methods for reducing the cold flow and the solutionviscosity of a diene rubber, and such methods can comprise combining(e.g., blending, mixing, compounding, etc.) the diene rubber with aconjugated diene monovinylarene block copolymer to form a cold flowresistant composition. In these and other embodiments disclosed herein,the cold flow resistant composition can have both a solution viscosityand a cold flow which are less than the respective solution viscosityand cold flow of the diene rubber. Generally, the features of any of thecompositions and methods disclosed herein (e.g., the diene rubber, thecold flow of the diene rubber, the solution viscosity of the dienerubber, the conjugated diene monovinylarene block copolymer, therelative amounts of the diene rubber and the conjugated dienemonovinylarene block copolymer in the composition, the cold flow of thecomposition, the solution viscosity of the composition, among others)are independently described herein, and these features can be combinedin any combination to further describe the disclosed compositions andmethods.

The conjugated diene monovinylarene block copolymer can be combined(blended, mixed, compounded, etc.) with the diene rubber to form thecold flow resistant composition by any means know to those of skill inthe art. Moreover, the conjugated diene monovinylarene block copolymercan be combined with the diene rubber at various steps within and/orafter the rubber formation process, as would be recognized by those ofskill in the art. For example, and not limited thereto, the conjugateddiene monovinylarene block copolymer can be fed to an extruder thatprocesses the rubber prior to baling, the conjugated dienemonovinylarene block copolymer can added to a finished rubber cement,the conjugated diene monovinylarene block copolymer can be added torubber crumples, the conjugated diene monovinylarene block copolymer canblended with the rubber in a steam stripper, and/or the conjugated dienemonovinylarene block copolymer can be solution blended with the rubberand then processed conventionally.

While not being limited thereto, particular embodiments contemplatedherein are directed to cold flow resistant compositions in which thecomposition is in the form of a solid. For instance, in one embodiment,the composition can be a solid at a temperature of 25° C. (e.g., aboutambient temperature). In another embodiment, the composition can be asolid at 40° C., at 50° C., or at 75° C. In yet another embodiment, thecomposition can be a solid at 100° C., at 125° C., or at 150° C. or evenhigher temperatures. In accordance with this disclosure, the cold flowresistant composition often can be described as a solid, and this ismeant to encompass high viscosity liquids, as would be recognized bythose of skill in the art. One particular solid form of the cold flowresistant composition can be a bale, which generally refers to a slab orblock of rubber, which often can range in weight from 20 to 50 kg (e.g.,about 30-31 kg), but not being limited thereto. Many commerciallyavailable diene rubber materials are shipped and/or stored in the formof a bale.

Additionally, or alternatively, the cold flow composition can besubstantially free of a solvent. In this context, “substantially free”means that the composition (i.e., containing a diene rubber and aconjugated diene monovinylarene block copolymer) contains less than 1wt. % solvent. For instance, the composition can contain less than 0.5wt. % solvent, less than 0.25 wt. % solvent, less than 0.1 wt. %solvent, less than 0.05 wt. % solvent, or less than 0.01 wt. % solvent,based on the total weight of the composition. Accordingly, cold flowcompositions that are substantially free of a solvent generally do notencompass mixtures of a diene rubber and a conjugated dienemonovinylarene block copolymer in a solvent (or monomer) such astoluene, xylene, benzene, ethylbenzene, styrene, methylstyrene,acrylonitrile, and the like.

According to another embodiment of the invention, a method forstorage-stabilizing a bale of diene rubber is provided herein, and thismethod can comprise adding a conjugated diene monovinylarene blockcopolymer to the diene rubber to form a cold flow resistant composition.The resultant cold flow resistant composition can have both a solutionviscosity and a cold flow which are less than the respective solutionviscosity and cold flow of the diene rubber. In this embodiment,“storage-stabilizing” a bale of rubber is meant to encompass, forexample, stabilizing the bale during long-term storage at ambient orelevated temperatures, stabilizing the bale during shipping at ambientor elevated temperatures (e.g., transport-stabilizing), and so forth. Asnoted hereinabove, the features of this method of storage-stabilizing abale of diene rubber disclosed herein (e.g., the diene rubber, the coldflow of the diene rubber, the solution viscosity of the diene rubber,the conjugated diene monovinylarene block copolymer, the relativeamounts of the diene rubber and the conjugated diene monovinylareneblock copolymer in the composition, the cold flow of the composition,the solution viscosity of the composition, among others) areindependently described herein, and these features can be combined inany combination to further describe the disclosed storage-stabilizingmethods.

Bales disclosed herein can contain a cold flow resistant composition,e.g., a diene rubber and a conjugated diene monovinylarene blockcopolymer, and these bales can have improved dimensional stability overa wide range of temperatures and time periods, as compared to balescontaining only the diene rubber. By describing the bale as being“dimensionally stable,” it is meant that the difference incross-sectional area of the bottom surface of the bale from thebeginning to the end of the time/temperature condition is within +/−10%.In one embodiment, for example, the cold flow resistant bale can bedimensionally stable at 25° C. for at least 1 day; alternatively, for atleast 1 week; alternatively, for at least 1 month; alternatively, for atleast 6 months, or alternatively, for at least 1 day up to 12 months. Inanother embodiment, the bale can be dimensionally stable at 35° C. forat least 1 day; alternatively, for at least 1 week; alternatively, forat least 1 month; alternatively, for at least 6 months; oralternatively, for at least 1 day up to 12 months. In yet embodiment,the bale can be dimensionally stable at 45° C. for at least 1 day;alternatively, for at least 1 week; alternatively, for at least 1 month;alternatively, for at least 6 months; or alternatively, for at least 1day up to 12 months. In still another embodiment, the bale can bedimensionally stable at 60° C. for at least 1 day; alternatively, for atleast 1 week; alternatively, for at least 1 month; alternatively, for atleast 6 months; or alternatively, for at least 1 day up to 12 months.

A feature of the compositions and methods disclosed herein can be animprovement in cold flow performance of the composition as compared tothe diene rubber alone. For instance, the cold flow resistantcomposition can have a “cold flow” which is less than the respectivecold flow of the diene rubber. The cold flow is measured in accordancewith the procedure described herein below and in U.S. Pat. No.3,758,656, which is incorporated by reference in its entirety. Manycommercially available diene rubbers can have a measured cold flow of atleast 25%, at least 30%, at least 35%, at least 40%, or at least 50%,and occasionally, as high as 60-70%. Such rubber materials are notdimensionally stable over a wide range of temperatures and time periods.Cold flow resistant compositions, on the other hand, can have much lowermeasured cold flow percentages, for instance, less than 30%, less than25%, less than 20%, less than 15%, less than 10%, or less than 5%.Moreover, the cold flow of the composition can be less than 1%, orsubstantially zero (i.e., no measurable cold flow), in certainembodiments.

The improvement in cold flow of the composition as compared to that ofthe diene rubber can be determined by the difference between themeasured cold flow of the composition and the measured cold flow of thediene rubber. The cold flow testing is on the same equipment/apparatusand under the same test procedures/conditions. In one embodiment, thecold flow of the composition can be at least 10 percentage points lessthan the cold flow of the diene rubber (e.g., up to 70 percentage pointsless, or up to 60 percentage points less, or to 50 percentage pointsless, or up to 40 percentage points less). In another embodiment, thecold flow of the composition can be at least 20 percentage points lessthan the cold flow of the diene rubber. Yet, in another embodiment, thecold flow of the composition can be at least 30 percentage points lessthan the cold flow of the diene rubber. As an example, if the measuredcold flow of the composition is 13%, and the measured cold flow of thediene rubber is 47%, then the cold flow of the composition would be atleast 30 percentage points less than the cold flow of the diene rubber(47% minus 13% equals 34%).

Typically, prior endeavors to improve the cold flow performance (e.g.,less cold flow) of a diene rubber have resulted in higher viscosities.For instance, reducing cold flow of a diene rubber often can require anincreased viscosity of the diene rubber, or an increased viscosity ofthe formulation containing the diene rubber. In some embodiments,reducing cold flow of a diene rubber can involve the use of methods tointroduce branching in the diene rubber or blending the diene rubberwith a branched material. For instance, reducing cold flow of a dienerubber can involve the use of a multi-functional monomer such asdivinylbenzene, or the introduction of crosslinking. However, thesemethods often increase the viscosity of the formulation containing thediene rubber. Unexpectedly, and in accordance with the presentinvention, the composition with improved cold flow performance (e.g.,less cold flow) also can have a solution viscosity that is less thanthat of the diene rubber. The solution viscosity testing is on the sameequipment/apparatus and under the same test procedures/conditions. Whilenot wishing to be bound by theory, Applicants believe that a lowerviscosity can be beneficial in the processing and production of highimpact polymer compositions, such as high impact polystyrene (HIPS). Insome embodiments, the solution viscosity of the composition can be atleast 10% less than the solution viscosity of the diene rubber, while inother embodiments, the solution viscosity of the composition can be atleast 25% less than the solution viscosity of the diene rubber. Yet, infurther embodiments, the solution viscosity of the composition can be atleast 40% less, at least 50% less, at least 60%, at least 75% less, atleast 85% less, at least 90% less, from at least 10% up to 99% less,from at least 25% up to 98% less, or from at least 40% up to 95% less,than the solution viscosity of the diene rubber. As an example, if themeasured solution viscosity of the composition is 700 cP, and themeasured solution viscosity of the diene rubber is 5,000 cP, then thesolution viscosity of the composition would be at least 85% less thanthe solution viscosity of the diene rubber (4,300 divided by 5,000equals 86%).

While not being limited thereto, the cold flow resistant compositionoften can comprise from about 5 to about 50 wt. % of the conjugateddiene monovinylarene block copolymer. This weight percentage is based onthe total weight of the composition. Suitable ranges for the weightpercentage of the conjugated diene monovinylarene block copolymer, basedon the total weight of the composition, can include, but are not limitedto, the following ranges: from about 10 to about 40 wt. %, from about 15to about 40 wt. %, from about 10 to about 30 wt. %, from about 15 toabout 30 wt. %, from about 10 to about 25 wt. %, or from about 15 toabout 25 wt. %, and the like. The specific amount of the conjugateddiene monovinylarene block copolymer utilized in the composition candepend on the desired cold flow characteristics, the desired viscosity,the anticipated storage/shipping temperature and time conditions, thegrade of diene rubber, the grade of the conjugated diene monovinylareneblock copolymer, amongst other variables.

Another feature of the compositions and methods disclosed herein can bea Dimensional Stability Factor (DSF) of greater than 2. The DSF ismeasured in accordance with the procedure described herein below forExamples 75-90, and uses data from an extended 16-hr cold flow test. TheDSF is the ratio of the stress of the composition after a 16-hr coldflow test to the stress of a standard single bale of rubber. Using thetest procedure described herein, the maximum DSF is about 6.4 (i.e.,with no measurable cold flow in 16 hr). In some embodiments, thedisclosed cold flow resistant compositions can have a DSF of greaterthan or equal to 2.5, or greater than or equal to 3.0, or from 2.5 toabout 6.4, or from 3.0 to about 6.4, while in other embodiments, thedisclosed cold flow resistant compositions can have a DSF of greaterthan or equal to 3.5, greater than or equal to 4.0, greater than orequal to 4.5, greater than or equal to 5.0, from 4.0 to about 6.4, orfrom 5.0 to about 6.4.

Conjugated Diene Monovinylarene Block Copolymers

Consistent with embodiments disclosed herein, the addition of aconjugated diene monovinylarene block copolymer to a diene rubber canresult in a composition having less cold flow and a lower solutionviscosity than that of the diene rubber in the absence of the conjugateddiene monovinylarene block copolymer. While not being limited thereto,certain suitable conjugated diene monovinylarene block copolymers thatcan be employed in various embodiments of this invention are describedin U.S. Pat. Nos. 3,639,517, 6,096,828, 6,420,486, 6,444,755, 6,835,778,7,037,980, 7,193,014, and 7,875,678, the disclosures of which areincorporated herein by reference in their entirety; and U.S. PatentPublication Nos. 2006/0089457, 2007/0173605, and 2008/0134642, thedisclosures of which are incorporated herein by reference in theirentirety.

The relative amount of conjugated diene and monovinylarene in the blockcopolymer utilized in the composition can depend on many variables, suchas on the desired cold flow characteristics, the desired viscosity, theanticipated storage/shipping temperature and time conditions, the gradeof diene rubber, the amount of the conjugated diene monovinylarene blockcopolymer used in the composition, amongst other variables. Nonetheless,the conjugated diene monovinylarene block copolymer typically can havefrom about 15 to about 95 wt. %, or from about 25 to about 95 wt. %,monovinylarene monomer content, based on the total weight of the (final)block copolymer. In some embodiments, the conjugated diene can be themajor component, and the conjugated diene monovinylarene block copolymercan have from about 20 to about 50 wt. % monovinylarene monomer content,from about 25 to about 50 wt. % monovinylarene monomer content, fromabout 20 to about 45 wt. % monovinylarene monomer content, or from about25 to about 45 wt. % monovinylarene monomer content, based on the totalweight of the block copolymer. In other embodiments, the monovinylarenecan be the major component, and the conjugated diene monovinylareneblock copolymer can have from about 50 to about 95 wt. % monovinylarenemonomer content, from about 50 to about 80 wt. % monovinylarene monomercontent, from about 55 to about 85 wt. % monovinylarene monomer content,or from about 65 to about 80 wt. % monovinylarene monomer content, basedon the total weight of the block copolymer.

In an embodiment of this invention, the conjugated diene monovinylareneblock copolymer can comprise an uncoupled conjugated dienemonovinylarene block copolymer. Uncoupled block copolymers often can bereferred to in the art as terminated or quenched copolymers. In furtherembodiments, the conjugated diene monovinylarene block copolymer cancomprise an uncoupled unimodal conjugated diene monovinylarene blockcopolymer, or alternatively, the block copolymer can comprise anuncoupled multimodal conjugated diene monovinylarene block copolymer.

In an embodiment of this invention, the conjugated diene monovinylareneblock copolymer can comprise a coupled conjugated diene monovinylareneblock copolymer, and further, the coupled conjugated dienemonovinylarene block copolymer can be a coupled unimodal conjugateddiene monovinylarene block copolymer or a coupled multimodal conjugateddiene monovinylarene block copolymer. In some embodiments, the blockcopolymer can be produced by coupling at least two different livingpolymer chains having been produced by at least two separate charges ofinitiator.

In an embodiment, the conjugated diene monovinylarene block copolymercan comprise a multimodal conjugated diene monovinylarene blockcopolymer containing at least two modes. In another embodiment, theblock copolymer can comprise at least 2 blocks selected from anycombination of conjugated diene blocks, monovinylarene blocks, orconjugated diene monovinylarene mixed blocks. Alternatively, the blockcopolymer can comprise at least 3 blocks, at least 4 blocks, or at least5 blocks, selected from any combination of conjugated diene blocks,monovinylarene blocks, or conjugated diene monovinylarene mixed blocks.For example, the conjugated diene monovinylarene block copolymer cancomprise from 3 to 10 blocks, from 4 to 7 blocks, or from 4 to 5 blocks,selected from any combination of conjugated diene blocks, monovinylareneblocks, or conjugated diene monovinylarene mixed blocks. In these andother embodiments, the first two blocks can be monovinylarene blocksand, additionally or alternatively, the last block prior to the couplingagent can be a conjugated diene block. In accordance with thisdisclosure, repeated blocks with an intervening charge of initiator arenot considered to be one block. Likewise, repeated mixed blocks also arenot considered to be one block.

In certain embodiments, the block copolymer can comprise a plurality ofmixed conjugated diene monovinylarene blocks, wherein each mixedconjugated diene monovinylarene block can contain conjugated diene unitsand monovinylarene units with a weight ratio of conjugated diene unitsto monovinylarene units in a range from about 0.05 to about 0.33, fromabout 0.6 to about 0.28, or from about 0.08 to about 0.26.

Also contemplated herein are block copolymers that can comprise mixedconjugated diene monovinylarene blocks selected from random blocks,tapered blocks, or combinations thereof. For instance, in oneembodiment, the conjugated diene monovinylarene block copolymer cancomprise at least three consecutive conjugated diene monovinylarenemixed blocks. In another embodiment, the block copolymer can comprise atleast three consecutive tapered mixed blocks. In yet another embodiment,the block copolymer can comprise at least three consecutive random mixedblocks.

In accordance with the present invention, the conjugated dienemonovinylarene block copolymer can comprise a block structure having theformula:i1−(D/A)_(m)−i2−(D/A)_(n)−i3−(D/A)_(p)−i4−(D/A)_(q)−i5−(D/A)_(r)−X.In this formula, A can be a monovinylarene in the range of 0 to 50 phr(i.e., parts per hundred monomers by weight), and D can be a conjugateddiene or mixture of different conjugated dienes in the range of 0 to 50phr, with A and D totaling 100 parts. D/A can be a mixture of conjugateddiene(s) and monovinylarene, with the ratio of D/A in each block beingthe same or different, and typically in the range of from 0:50 to 50:0phr. Independently, i1 to i5 can be initiating catalysts in a range from0 to 0.2 phr, the presence of which can start a new polymer chain. Alsoindependently, m, n, p, q, and r can be integers in a range from 0 to 3,inclusive. X in the above formula can be a coupling agent or aterminator.

The conjugated diene monovinylarene block copolymer can comprise atleast one of the following block structures in another embodimentconsistent with this disclosure:i-S-S-i-S-B-X;  (A)i-S-i-S-B-i-S-B-X;  (B)i-S-i-S-(B/S)-i-S-B-X;  (C)i-S-i-S-(B/S)-(B/S)-X;  (D)i-S-i-S-(B/S)-(B/S)-B-X;  (E)i-S-i-S-(B/S)-(B/S)-(B/S)-X;  (F)i-S-i-S-(B/S)-(B/S)-(B/S)-B-X;  (G)i-S-i-S-(B/S)-(B/S)-(B/S)-(B/S)-X;  (H)ori-S-i-S-(B/S)-(B/S)-(B/S)-(B/S)-B-X.  (I)In formulas (A) to (I), S can be a styrene block, B can be a conjugateddiene block, and B/S can be a conjugated diene monovinylarene mixedblock. Each i independently can be an initiator, the presence of whichcan start a new polymer chain. X in these formulas can be a couplingagent or a terminator.

Various monovinylarenes and conjugated dienes can be used to form blockcopolymers that are suitable for use in the disclosed cold flowresistant compositions. While not being limited thereto, themonovinylarene often can contain from 8 to 18 carbon atoms (e.g., themonovinylarene can be styrene), and the conjugated diene can containfrom 4 to 12 carbon atoms (e.g., the conjugated diene can be abutadiene, such as 1,3-butadiene). Accordingly, in a particularembodiment disclosed herein, the conjugated diene monovinylarene blockcopolymer can comprise a styrene butadiene block copolymer (SBC).

Many commercially available styrene butadiene block copolymers can beemployed in the cold flow resistant compositions described herein,including, but not limited to, K-Resin® SBC grades available fromChevron Phillips Chemical Company LP, such as, for instance, DK11, KR52,KR53, XK40, KR05, and KK38; SBC grades available from Styrolution, suchas, for instance, 3G46, 3G55 and 2G66; SBC grades available from DexcoPolymers, such as, for instance, Vector® 8508, Vector® 6507, and Vector®6241; SBC grades available from Kraton Performance Polymers, such as,for instance, D1155, D1118, D1116, and D1124; SBC grades available fromLCY Chemical Industry Corp., such as, for instance, LCY3527 and LCY3114;SBC grades available from SINOPEC Corporation (China Petroleum &Chemical Corporation); SBC grades available from Denka (Denki KagakuKogyo K.K.; Denka Chemical Holdings Asia Pacific Pte Ltd.); SBC gradesavailable from Asahi (Asahi Kasei Chemicals Corporation); and the like,as well as mixtures or combinations thereof.

Diene Rubbers

The type or grade of diene rubber that can benefit from the addition ofa conjugated diene monovinylarene block copolymer is not particularlylimited. As non-limiting examples, the diene rubber can comprise apolybutadiene, a polyisoprene, a poly-2-chloro-1,3-butadiene, apoly-1-chloro-1,3-butadiene, an ethylene/propylene terpolymer, abutadiene/acrylonitrile copolymer, a butyl rubber, an acrylic rubber, astyrene/isobutylene/butadiene copolymer, an isoprene/acrylic estercopolymer, and the like, as well as mixtures or combinations thereof. Incertain embodiments, the diene rubber can comprise a polybutadienerubber, and the polybutadiene rubber can be a high cis polybutadienerubber or a low cis polybutadiene rubber. In one embodiment, the dienerubber can comprise a high cis polybutadiene rubber that contains from60 to 95 mol % cis double bonds, while in another embodiment, the dienerubber can comprise a low cis polybutadiene rubber that contains from 20to 60 mol % cis double bonds. Yet, in other embodiments, the dienerubber can comprise a diene monovinylarene rubber, and further, thediene monovinylarene rubber can contain up to 40 wt. % styrene. Aparticular example of a diene monovinylarene rubber suitable for use asdescribed herein is styrene butadiene rubber (SBR).

Many commercially available diene rubbers suitable for use as describedherein can include, but are not limited to, Ubepol® BR15HB and BR14HBfrom Ube Industrial, Ltd.; Diene® 55AC10 and Diene® 35AC10 fromFirestone Polymers; Asadene 35AE, Asadene 55AE, and Asaprene 730AX,available from Asahi Kasei Chemicals Corporation; various rubber gradesavailable from SINOPEC Corporation (China Petroleum & ChemicalCorporation); and the like, and this includes mixtures or combinationsof two or more of these materials.

Impact Polymer Compositions

High impact polymer compositions can be produced from the cold flowresistant compositions disclosed herein. One such high impact polymercomposition can comprise (i) a monovinylarene-based polymer, and (ii)from about 1 to about 35 wt. % particles dispersed in the polymer, theparticles comprising any of the cold flow resistant compositionsdisclosed or described herein. In an embodiment, the high impact polymercomposition can comprise from about 2 to about 30 wt. %, or from about 3to about 30 wt. %, particles comprising the cold flow resistantcomposition. In another embodiment, the high impact polymer compositioncan comprise from about 4 to about 25 wt. % particles comprising thecold flow resistant composition. In yet another embodiment, the highimpact polymer composition can comprise from about 5 to about 20 wt. %,or from about 8 to about 18 wt. %, particles comprising the cold flowresistant composition. In these and other embodiments, at least aportion of the monovinylarene-based polymer can be grafted with the coldflow resistant composition. The cold flow resistant composition can begrafted with the monovinylarene-based polymer to the extent that thereis at least a portion of the monovinylarene-based polymer present asgrafts on the cold flow resistant composition. For instance, the coldflow resistant composition can represent a main chain and the graftedmonovinylarene-based polymer can represent side chains composed ofmonovinylarene homopolymers or copolymers.

The monovinylarene-based polymer can comprise a polystyrene in oneembodiment, and accordingly, the high impact polymer composition cancomprise a high impact polystyrene. In another embodiment, themonovinylarene-based polymer can be a copolymer derived from amonovinylarene monomer and an acrylic monomer, or alternatively, themonovinylarene-based polymer can be a copolymer derived from amonovinylarene monomer and a methacrylate monomer. Often, in theseembodiments, the monovinylarene-based polymer can have from about 55 toabout 95 wt. % monovinylarene monomer content, based on the total weightof the polymer. For example, the monovinylarene-based polymer can havefrom about 55 to about 80%, or from about 65 to about 85 wt. %,monovinylarene monomer content, based on the total weight of thepolymer. In some embodiments, the monovinylarene monomer can be styrene,the acrylic monomer can be acrylonitrile, and the high impact polymercomposition can be an acrylonitrile butadiene styrene polymer (ABS). Inother embodiments, the monovinylarene monomer can be styrene, themethacrylate monomer can be methyl methacrylate, and the high impactpolymer composition can be a methyl methacrylate butadiene styrenepolymer (MBS).

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Solution viscosities (cP or Pa-s) were measured in 14% solids in toluenewith a Brookfield R/S-CPS+ Rheometer at 30° C., unless stated otherwise.

Mooney Viscosity measurements (ML/4/100° C.) were determined inaccordance with ASTM 1646-95.

Cold flow measurements (%) were conducted as follows. The test material(base rubber, mixture of rubber and SBC, etc.) was dissolved in THF,mixed thoroughly, and dried in a vacuum to remove the solvent. Then, thetest material was molded at 350° F. (177° C.) into a cylindricalspecimen having a diameter of ¾″ (1.9 cm) and a height of ½″ (1.27 cm).The test specimen and a 350 g cylinder with a 3-inch (7.6 cm) diameterwere preconditioned at 150° F. (65° C.) for 1 hr. Then, the testspecimen was compressed by the 350 g weight for 1 hr at 150° F. (65° C.)as described in U.S. Pat. No. 3,758,656, the disclosure of which isincorporated herein by reference in its entirety. The specimen heightsbefore and after the test are referred to as h_(o) and h_(f),respectively, with the cold flow (measured in %) determined by theequation: 100×(h_(o)−h_(f))/h_(o). Cold flow percentages listed in theexamples that follow reflect an average of two measurements.

Styrene percentage (%) in the examples that follow is the styrenemonomer content in the block copolymer. In the case of general purposepolystyrene, the styrene monomer content is listed as 100%.

Grades of styrene butadiene block copolymers were obtained from ChevronPhillips Chemical Company LP, Styrolution, Dexco Polymers, KratonPerformance Polymers, and LCY Chemicals. SBC grades were given numericaldesignations and have the following respective styrene contents:

 SBC 1 (76% styrene)  SBC 2 (74% styrene)  SBC 3 (75% styrene)  SBC 4(70% styrene)  SBC 5 (29% styrene)  SBC 6 (43% styrene)  SBC 7 (51%styrene)  SBC 8 (65% styrene)  SBC 9 (62% styrene) SBC 10 (43% styrene)SBC 11 (40% styrene) SBC 12 (40% styrene) SBC 13 (33% styrene) SBC 14(29% styrene) SBC 15 (25% styrene) SBC 16 (23% styrene) SBC 17 (30%styrene, SIS copolymer)

Examples 1-5

Table I summarizes the viscosity and cold flow properties of variouscommercial grades of rubber available from Ube Industrial, Ltd.,Firestone Polymers, Asahi Kasei Chemicals Corporation, and SINOPECCorporation. The cold flows for these rubbers were at least 35%, andranged to over 65%.

TABLE I Examples 1-5. Dilute Solution Solution Cold Rubber ViscosityViscosity Mooney Flow Example Grade (cP) (cP)^(A) Viscosity^(B) (%) 1BR1 5,200 60 40 37 2 BR2 5,100 85 33 67 3 BR3 1,600 35 47 59 4 BR4 2,400— — 51 5 BR5 17,400 170  55 46 ^(A)Data for Dilute Solution Viscositywith 5% solids in toluene was provided by the supplier of the rubbergrade. ^(B)Data for Mooney Viscosity was provided by the supplier of therubber grade.

Examples 6-14

Table II summarizes viscosity and cold flow properties for neat BR4 andfor mixtures with 25 wt. % of styrene block copolymers having a range ofstyrene monomer contents. Also included in Table II are viscosities forneat BR5 and for mixtures with 25 wt. % of styrene block copolymershaving a range of styrene monomer contents. Unexpectedly, the additionof 25% of the styrene block copolymer both significantly reduced thecold flow and significantly reduced the viscosity. Interestingly, theaddition of 25% of a styrene block copolymer having 70-80% styrenecontent completely eliminated the cold flow (i.e., cold flow is zeropercent), as measured by the cold flow test described hereinabove.

TABLE II Examples 6-14. Cold Rubber SBC Styrene Viscosity Flow ExampleGrade Grade (%) (Pa-s)^(C) (%)  6 BR5 — — 164  41   7A BR5 SBC 1 76 16 — 7B BR4 SBC 1 76 — 0  8A BR5 SBC 2 74 19 —  8B BR4 SBC 2 74 — 0  9A BR5SBC 3 75 11 —  9B BR4 SBC 3 75   13.4 0 10A BR5 SBC 4 70 10 — 10B BR4SBC 4 70   7.4 0 11A BR5 SBC 5 29 71 — 11B BR4 SBC 5 29  40^(D) 30  12BBR4 SBC 6 43 — 24  13B BR4 SBC 7 51 — 6 14 BR4 — — 50 47  ^(C)For BR5,viscosity data at 14% solids in 60/40 toluene/methyl methacrylate (MMA).For BR4, viscosity data at 14% solids in toluene (solution viscosity).^(D)Estimated from trend line of concentration-viscosity relationship.

Examples 15-22

Table III summarizes the effects of the addition of various weightpercentages of SBC 4 (70% styrene monomer content) on the solutionviscosities of BR5, BR4, and BR1, as well as on the cold flow of BR4.The surprising result of a concurrent reduction in viscosity and in coldflow as the percentage of SBC 4 increases is evident from Table III.Example 20 demonstrates that a mixture of 25% SBC 4 with BR4 wassufficient to completely eliminate cold flow.

TABLE III Examples 15-22. BR5 BR4 BR1 BR4 SBC Solution Solution SolutionCold Weight Viscosity Viscosity Viscosity Flow Example (%) (cP) (cP)(cP) (%) 15 0 17,400 2,400 5,100 47 16 5 7,600 — 2,300 49 17 10 4,2001,900 1,500 35 18 15 1,800 1,700 1,100 36 19 20 1,700 — 740 14 20 25 390— 270  0 21 50 150   260 130 — 22 100 44   38 39 —

Examples 23-30

Table IV summarizes the effects of the addition of various weightpercentages of SBC 5 (29% styrene monomer content) on the solutionviscosity of BR5, as well as on the cold flow of BR4. Similar toExamples 15-22, Examples 23-30 demonstrate the surprising result of aconcurrent reduction in viscosity and in cold flow as the percentage ofSBC 5 increases. With the lower styrene monomer content, amounts of SBC5 over 30% were required to achieve a significant reduction in the coldflow of BR4.

TABLE IV Examples 23-30. BR5 BR4 SBC Solution Cold Weight Viscosity FlowExample (%) (cP) (%) 23 0 17,400  47 24 10 8,500 42 25 15  6,100^(E) 4026 20 5,000 29 27 25  4,000^(E) 29 28 37.5  2,800^(E) 11 29 50 2,000  930 100 1,300 — ^(E)Estimated from trend line of concentration-viscosityrelationship.

Examples 31-33

Table V summarizes the effects of the addition of various weightpercentages of a general purposed polystyrene (100% styrene monomercontent, grade EA3400, commercially available from Americas Styrenics)on the cold flow of BR4. Interestingly, polystyrene was not effective atreducing cold flow. For instance, the cold flow in Example 33 at 20%polystyrene loading was 39%, while it was 29% for Example 26 (20% SBC 5with only 29% styrene monomer) and 14% for Example 19 (20% SBC 4 with70% styrene monomer).

TABLE V Examples 31-33. Polystyrene BR4 Weight Cold Flow Example (%) (%)31 10 43 32 15 37 33 20 39

Examples 34-49

Table VI summarizes the effect of styrene monomer content of the styreneblock copolymer on the cold flow of BR4 at a 20 wt. % loading of thestyrene block copolymer. Generally, SBC grades with greater than 50%styrene monomer content resulted in much greater cold flow reductionthat those with less than 50% styrene monomer content.

TABLE VI Examples 34-49. SBC Styrene Cold Flow Example Grade (%) (%) 34SBC 1 76 8 35 SBC 3 75 5 36 SBC 4 70 13 37 SBC 8 65 32 38 SBC 9 62 13 39SBC 7 51 12 40 SBC 10 43 18 41 SBC 6 43 26 42 SBC 11 40 28 43 SBC 12 4033 44 SBC 13 33 29 45 SBC 14 29 32 46 SBC 5 29 29 47 SBC 15 25 38 48 SBC16 23 26 49 SBC 17 30 29

Examples 50-57

Table VII summarizes the effect of styrene monomer contents of thestyrene block copolymer on the cold flow of BR4 at a 5 wt. % and a 10wt. % loading of the styrene block copolymer. With neat BR4 having acold flow of 47%, only the SBC with 76% styrene monomer of Example 51resulted in an appreciable reduction in cold flow at a 5 wt. % loading.At 10 wt. %, the general purpose polystyrene (Example 50) provided nobenefit, while the SBC's with 65-76% styrene monomer (Examples 51-54)resulted in at least a 10 percentage point reduction in cold flow.

TABLE VII Examples 50-57. Cold Flow Cold Flow Styrene With 5% SBC With10% SBC Example (%) (%) (%) 50 100 — 43 51 76 29 24 52 75 48 34 53 70 4935 54 65 — 34 55 51 50 40 56 43 41 47 57 29 42 40

Examples 58-63

Table VIII summarizes the effect of styrene monomer content of thestyrene block copolymer on the cold flow of BR2 at a 20 wt. % loading ofthe styrene block copolymer. Neat BR2 rubber had the highest cold flowof any of the grades of rubber tested (67%). Nonetheless, the additionof 20 wt. % of an SBC dramatically reduced cold flow, regardless ofstyrene monomer content. Most effective in reducing cold flow were SBCgrades with 70% or greater styrene monomer (Examples 58-60); inparticular, SBC 1 almost completely eliminated the cold flow of BR2(i.e., the cold flow was 1%).

TABLE VIII Examples 58-63. SBC Styrene Cold Flow Example Grade (%) (%)58 SBC 3 75 6 59 SBC 4 70 12 60 SBC 1 76 1 61 SBC 8 65 23 62 SBC 6 43 1463 SBC 14 29 34

Examples 64-74

Table IX summarizes the effect of the addition of various weightpercentages of styrene block copolymers and the effect of styrenemonomer content on the cold flow of BR4. In general, the addition of astyrene block copolymer to the butadiene rubber improved the cold flowperformance, with higher weight percentages of the styrene blockcopolymer typically resulting in better cold flow performance (e.g., 15wt. % or more). SBC grades with 50% or greater styrene monomer content,but less than 100% (i.e., not the polystyrene of Example 64), were moreeffective in improving cold flow.

TABLE IX Examples 64-74. Sty- Exam- rene % Cold Flow with 5% to 50% ofthe SBC in BR4 ple (%) 5% 10% 15% 20% 25% 30% 37.5% 50% 64 100 — 43 3639 — — — — 65 76 29 24 33 8 0 — — — 66 75 48 34 24 5 0 — — — 67 70 49 3536 13 0 — — — 68 65 — 34 36 32 13 — — — 69 62 — — — 13 — — — — 70 51 5040 31 12 6 5 — — 71 43 41 47 38 26 24 — 9 — 72 40 — — — 30 — — — — 73 2942 40 29 29 11 — 11 9 74 25 — — — 38 — — — —

Examples 75-90

Table X summarizes the Dimensional Stability Factor for neat BR1, BR2,and BR4, and for various mixtures of BR2 or BR4 with styrene butadieneblock copolymers having a range of styrene monomer contents. TheDimensional Stability Factor (DSF, unit-less) was determined bycalculating the final stress in an extended 16-hr cold flow test, anddividing this final stress by the stress of a standard single bale ofrubber. A standard single bale of rubber used in the DSF determinationwas a 70 cm length×35 cm width×21 cm height bale of rubber having a0.913 g/cm³ density. Using the bale volume and rubber density, the massof the bale was calculated to be about 47 Kg, with a resultinggravitational force of 460 N. The stress of the standard single bale ofrubber was determined by dividing the force by the surface area of thebale (0.7 m×0.35 m). Thus, the stress of the standard single bale ofrubber was 1878 Pa (0.272 psi), and this value is used for thecalculation of all DSF's provided herein.

The final stress in the extended 16-hr cold flow test was determined asfollows. The test material (base rubber, mixture of rubber and SBC,etc.) was dissolved in THF, mixed thoroughly, and dried in a vacuum toremove the solvent. Then, the test material was molded at 350° F. (177°C.) into a cylindrical specimen having a diameter of ¾″ (1.9 cm) and aheight of ½″ (1.27 cm). The test specimen and a 350 g cylinder with a3-inch (7.6 cm) diameter were preconditioned at 150° F. (65° C.) for 1hr. Then, the test specimen was compressed by the 350 g weight for 16 hrat 150° F. (65° C.) as described hereinabove and in U.S. Pat. No.3,758,656. The specimen height after the 16-hr test was measured andrecorded.

For illustration purposes, the determination of the final stress in theextended 16-hr cold flow test for Example 75 is described, having afinal specimen height of 0.312 in (0.8 cm). The initial volume of thecylindrical specimen was 3.62 cm³ (0.22 in³). Ignoring the elasticcompressibility of the rubber samples for these calculations, the finalvolume of the cylindrical sample after 16 hr will be the same as theinitial volume and, therefore, the surface area of Example 75 at the endof the 16-hr test was 4.5 cm². The 350 g weight exerts a force of 3.43N, and after dividing by the final surface area of Example 75, the finalstress in the extended 16-hr cold flow test was about 7600 Pa (1.1 psi).The DSF for Example 75 was determined by the ratio, 7600 Pa/1878 Pa,which equates to 4.0. The respective DSF for Examples 76-90 wasdetermined in the same manner, using the final specimen height after theextended 16-hr test as the measurable variable.

Interestingly, as shown in Table X, the addition of 20% of a styreneblock copolymer having 70% or more styrene content resulted inDimensional Stability Factors (DSF's) of at least 4.0 for compositionscontaining BR2 and BR4. Without the SBC addition, the DSF's of neat BR2and BR4 were 1.6 and 1.9, respectively (i.e., less than 2).

TABLE X Examples 75-90. SBC Rubber SBC Styrene Weight Example GradeGrade (%) (%) DSF 75 BR4 SBC 4 70 20 4.0 76 BR4 SBC 1 76 20 5.4 77 BR4SBC 6 43 20 3.2 78 BR4 SBC 7 51 20 4.2 79 BR4 SBC 8 65 20 2.7 80 BR4 — —0 1.9 81 BR1 — — 0 3.0 82 BR4 SBC 5 29 20 2.7 83 BR4 SBC 3 75 20 4.4 84BR4 SBC 3 75 15 3.0 85 BR4 SBC 3 75 10 2.6 86 BR4 SBC 3 75 5 2.0 87 BR2SBC 4 70 20 4.4 88 BR2 SBC 1 76 20 5.8 89 BR2 SBC 5 29 20 2.1 90 BR2 — —0 1.6

We claim:
 1. A cold flow resistant composition comprising: (a) a dienerubber; and (b) a conjugated diene monovinylarene block copolymer, theconjugated diene monovinylarene block copolymer having from about 50 toabout 95 wt. % monovinylarene monomer content, based on the total weightof the block copolymer; wherein: a solution viscosity of the compositionis less than a solution viscosity of the diene rubber; a cold flow ofthe composition is less than a cold flow of the diene rubber; thecomposition contains less than 1 wt. % solvent; and the compositioncomprises from about 15 to about 30 wt. % of the conjugated dienemonovinylarene block copolymer, based on the total weight of thecomposition.
 2. The composition of claim 1, wherein the composition isin the form of bale.
 3. The composition of claim 1, wherein: the coldflow of the diene rubber is at least 35%; the cold flow of thecomposition is less than 30%; the cold flow of the composition is atleast 10 percentage points less than the cold flow of the diene rubber;or any combination thereof.
 4. The composition of claim 1, wherein theconjugated diene monovinylarene block copolymer has from about 55 toabout 85 wt. % monovinylarene monomer content, based on the total weightof the block copolymer.
 5. The composition of claim 1, wherein the dienerubber comprises a polybutadiene rubber having from 60 to 95 mol % cisdouble bonds.
 6. The composition of claim 1, wherein the diene rubbercomprises a polybutadiene rubber having from 20 to 60 mol % cis doublebonds.
 7. The composition of claim 1, wherein: the diene rubbercomprises a polybutadiene rubber; and the conjugated dienemonovinylarene block copolymer comprises a styrene butadiene blockcopolymer.
 8. The composition of claim 1, wherein: the conjugated dienemonovinylarene block copolymer has from about 55 to about 85 wt. %monovinylarene monomer content, based on the total weight of the blockcopolymer; the conjugated diene monovinylarene block copolymer comprisesa styrene butadiene block copolymer; the cold flow of the composition isless than 30%; and the cold flow of the composition is at least 10percentage points less than the cold flow of the diene rubber.
 9. Thecomposition of claim 8, wherein: the conjugated diene monovinylareneblock copolymer has from about 65 to about 80 wt. % monovinylarenemonomer content, based on the total weight of the block copolymer; andthe cold flow of the composition is less than 15%.
 10. The compositionof claim 9, wherein the diene rubber comprises a polybutadiene rubber.11. The composition of claim 1, wherein the conjugated dienemonovinylarene block copolymer comprises a styrene butadiene blockcopolymer.
 12. The composition of claim 11, wherein the composition is asolid.
 13. The composition of claim 11, wherein the diene rubbercomprises a polybutadiene rubber having from 60 to 95 mol % cis doublebonds.
 14. The composition of claim 11, wherein the diene rubbercomprises a polybutadiene rubber having from 20 to 60 mol % cis doublebonds.
 15. The composition of claim 11, wherein the cold flow of thecomposition is less than 30%.
 16. The composition of claim 11, whereinthe cold flow of the composition is less than 15%.
 17. The compositionof claim 11, wherein the cold flow of the composition is at least 10percentage points less than the cold flow of the diene rubber.
 18. Thecomposition of claim 11, wherein the conjugated diene monovinylareneblock copolymer has from about 55 to about 85 wt. % monovinylarenemonomer content, based on the total weight of the block copolymer. 19.The composition of claim 11, wherein the conjugated diene monovinylareneblock copolymer has from about 65 to about 80 wt. % monovinylarenemonomer content, based on the total weight of the block copolymer.